A Comparative Study of Color Pattern Reversal Visual Evoked Potential in Type 2 Diabetics and Normal Individuals
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Dayananda G, Thejaswini KO, Ruthvik S Murthy, Srinivasa R
Volume : 2
Issue : 3
Online ISSN : 2394-2126
Print ISSN : 2394-2118
Article First Page : 117
Article End Page : 121
Introduction: Diabetes Mellitus (DM) is a globally present metabolic syndrome characterized by macro vascular and micro vascular damage. Commonest micro vascular complication is diabetic retinopathy (DR) which can cause visual impairment and sometimes also lead to blindness. It is observed that even before the onset of the micro vascular lesions of DR, the neural retina of the diabetic eye undergoes subtle functional changes, like the color vision. Electro physiologic techniques have served to detect early neuroretinal functional changes that occur in Type 2 Diabetes mellitus (T2DM). The color pattern reversal visual evoked potential (Color PRVEP) is a useful electro physiologic indicator of early color vision changes in DM.
Materials and Methods: The cross sectional case control study consisted of 30 subjects, 15 as Cases with newly diagnosed T2DM in the age group 35 to 40 years and 15 age and sex matched subjects without T2DM as Controls. PRVEP and color PRVEP were recorded from all subjects and the HbA1c was determined. An informed written consent to participate in the study was taken from the subjects. There was no financial burden on the subjects. The study protocol was approved by the Institutional Ethical Committee. All the quantitative data such as age, latency, duration of the diseases, HbA1c, P wave latency and amplitude were summarized and statistically analyzed.
Results: The basic characteristics with respect to age did not show any significant difference between the diabetics as compared to non diabetics (p<0.05). The HbA1c of diabetics was significantly increased as compared to non diabetics (p<0.05). The P100 latency after PRVEP and color PRVEP was significantly delayed (increased) in diabetics as compared to non diabetics (p<0.05). Pearson Correlation of HbA1c with P100 latencies in diabetics was statistically significant for Black / White PRVEP (p<0.05).
Conclusions: There is a delayed P100 latency observed in T2DM as compared to non diabetics. This delay could be of various possibilities and importantly due to demyelination which is the mainframe of the abnormal PRVEP. HbA1c does not correlate well with the PRVEP parameters in these newly detected diabetics. This warrants the possibilities of worsening scenario in long standing, chronic diabetes.
Key words: Color PRVEP, Color Vision, Diabetic Retinopathy, P100, T2DM